Method of preparing alkaline difluoromethane sulfonates

Abstract

A method of preparing alkaline difluoromethane sulfonates by reacting an alkali-metal sulfite of the formula M 2 SO 3 , in which M represents an alkali-metal of column 1 of the Periodic Table of the Elements, with at least an equimolecular quantity of chlorodifluoromethane in aqueous medium, in an autoclave under autogenous pressure, characterized by the fact that the reaction is carried out in the presence of at least one strong alkali-metal base of the formula M'OH, in which M' represents an alkali-metal of column 1 of the Periodic Table of the Elements.

What is claimed is: 
     
       1. A method of preparing alkaline difluoromethane sulfonates which comprises reacting an alkali-metal sulfite of the formula M 2  SO 3 , in which M represents an alkali-metal of column 1 of the Periodic Table of the Elements, with an at least equimolecular amount of chlorodifluoromethane, in an aqueous medium, in an autoclave under autogenous pressure, whereby the said reaction is carried out in the presence of at least one strong alkali-metal base of the formula M'OH in which M' represents an alkali-metal of column 1 of the Periodic Table of the Elements. 
     
     
       2. A method according to claim 1, wherein M' and M represent the same alkali-metal. 
     
     
       3. A method according to claim 1, wherein M' and M represent an alkali-metal selected from the class consisting of sodium and potassium. 
     
     
       4. A method according to claim 1, wherein the said alkali-metal base is used in such amount that the molar ratio of the alkali-metal base to the alkali-metal sulfite is between about 0.1 and about 1 to 1. 
     
     
       5. A method according to claim 4, wherein the molar ratio of the alkali-metal base to the alkali-metal sulfite is equal to about 0.5 to 1. 
     
     
       6. A method according to claim 1, wherein the reaction is carried out at a temperature of between about 100° C. and about 200° C. 
     
     
       7. A method according to claim 6, wherein the reaction is carried out at a temperature of about 150° C. 
     
     
       8. A method according to any one of claims 1 to 7, wherein the reaction is carried out in the presence of at least one phase transfer agent. 
     
     
       9. A method according to claim 8, wherein the said phase transfer agent is selected from the group consisting of quaternary ammonium salts and quaternary phosphonium salts. 
     
     
       10. A method according to claim 9, wherein the said quaternary ammonium salts and the said quaternary phosphonium salts have one of the following formulas:   R.sub.1 R.sub.2 R.sub.3 R.sub.4 N.sup.+ X.sup.-     and     R.sub.1 R.sub.2 R.sub.3 R.sub.4 P.sup.+ X.sup.-     in which R 1 , R 2 , R 3 , and R 4 , each represent a group selected from the class consisting of alkyl, aralkyl, and aryl radicals, having from about 1 to 24 carbon atoms, and X represents a member selected from the class consisting of a halogen atom and HSO 4   - .   
     
     
       11. A method according to claim 10, wherein the said quaternary ammonium and the said phosphonium salt is selected from the group consisting of: (C 6  H 5  CH 2 )N +  (CH 3 ) 3  Cl - , (C 4  H 9 ) 4  N +  Cl - , (C 8  H 17 ) 4  N +  Br - , (C 6  H 5  CH 2 )N +  (C 2  H 5 ) 3  Cl - , (C 4  H 9 ) 4  N +  HSO 4   - , (C 16  H 33 )P +  (C 4  H 9 ) 3  Br - , (C 16  H 33 )P +  (C 6  H 5 ) 3  Cl - , (C 6  H 5  CH 2 )P +  (C 6  H 5 ) 3  Cl - , and (C 4  H 9 ) 4  P +  Br - .   
     
     
       12. A method according to claim 9, wherein the molar ratio of the quaternary ammonium salt to the alkali-metal sulfite is between about 0.02 and about 0.1 to 1. 
     
     
       13. A method according to claim 12, wherein the molar ratio of the quaternary ammonium salt to the alkali-metal sulfite is equal to about 0.05 to 1. 
     
     
       14. A method according to claim 1, wherein the reaction is carried out in the presence of at least 200 ml. of water per mol of alkali-metal sulfite used. 
     
     
       15. A method according to claim 14, wherein the reaction is carried out in the presence of about 300 ml. to about 700 ml. of water per mol of alkali-metal sulfite used.